The major thrust of this program project is the pursuit of basic studes in chemistry and biology which will generate new information in the area of environmental health problems. The dearth of such basic information is a chronic problem for regulatory agencies and environmentalists alike. The long-range goal of this program project is to broaden the base of scientific information on which more reliable assessment of the relative risks of various environmental hazards can be made. This program is comprised of five projects which deal with (1) the role of oxidation reactions in biological systems; (2) the mechanism of action of polycyclic aromatic hydrocarbon epoxides, including (3) their interaction with the chromosomes and viruses; (4) chemical mechanistic approaches for evaluating the merits of various wastewater and water disinfectants; and (5) the effects of ultrasound on nucleic acids. Although a number of agents and different substrates are being studied, these systems have in common the fact that their actions are manifested through nucleic acids in the production of mutagenic effects. These projects are being pursued according to a course of action involving four stages of operation. The purpose of each stage is: 1) to establish procedures for the separation and characterization of major reaction products; 2) to develop methods for the synthesis of these products once they are identified, so that a sufficient supply of them will be available for stages 3 and 4; 3) to examine the apparent biological effects of each product in vitro and in vivo; 4) to study the molecular mechanism related to an observed biological phenomenon. Substantial progress has been achieved toward the respective goals in each project. The specifics are being described in our summary progress report. These studies will be continued in the direction as originally proposed. Accordingly, the research plans for the second year will be essentially unchanged as those initially submitted in our grant application.